This project supports collaboration with NCI researchers in the design, conduct, and statistical analysis of epidemiologic investigations. We are playing a major role in three large studies: (1) a case-control study of childhood acute lymphoblastic leukemia (ALL) examining possible associations between ALL and magnetic fields, proximity to overhead electric transmission lines, and residential exposure to pesticides, ionizing radiation, and radon; (2) the Agricultural Health Study, a prospective study of a cohort of 75,000 adults living on farms in Iowa and North Carolina to investigate potential disease risks associated with farming-related exposures; and (3) a randomized trial to determine if human papilloma virus DNA type can be used to determine the appropriate treatment for women with abnormal PAP smears. Additional studies for which assistance has been provided include: an investigation indicating that cigarette smoking and oral contraceptive use may be associated with increased risk of adrenal cancer; studies of factors associated with seroreactivity to HPV-16 virus-like particles; a study in Taiwan of a possible association between the risk of nasopharyngeal carcinoma and HLA type; investigations of whether service in Vietnam is associated with increased risk of cancer in military working dogs, in a large cohort of West Virginia veterans, and in a cohort of air force personnel who served in Vietnam or Thailand; a study performed to determine the frequency of common BRCA1 mutations in radiologic technologists who developed breast cancer or ovarian cancer before the age of 35; studies to examine the frequency of chromosome abnormalities in workers occupationally exposed to benzene or to pesticides; investigations of the frequency of second cancers and the frequency of lipomas in retinoblastoma (RB) patients; a study to determine if specific mutations in the RB gene result in a higher probability of developing a second cancer; investigations to determine if the frequency of stable chromosome aberrations or glycophorin A variant erythrocytes is related to lifetime occupational exposure to ionizing radiation in a U.S. cohort of radiologic technologists or in a cohort of workers at the Sellafield British Nuclear Fuels facility; and studies examining possible associations between HLA type and adult T-cell leukemia/lymphoma or infection with Human T-cell Lymphotropic Virus type 1.